1. Field of the Invention
The present invention generally relates to a filter for a recirculating tank and, more particularly, to a self contained filter for a recirculating tank used in a septic system.
2. Background Description
Septic systems are widely used for a variety of applications ranging from single family homes to industrial applications. These systems also vary greatly in design; namely, aerobic and anaerobic type systems. In either type of septic systems, the main objective is to treat wastewater in the most efficient manner in order to ensure that the water is properly filtered for distribution within a drain field or other distribution system.
In certain types of septic systems, a sand filter is used to filtrate the wastewater prior to further treating or distribution of the effluent. The sand filter is disposed within a recirculating tank and includes several layers of varying sized aggregate. For simplicity of discussion, the aggregate is manually disposed within the tank, with the larger sized aggregate on the bottom of tank and the smaller or finer sized aggregates progressively being layered toward the top of the tank. In some systems, one sized aggregate may be used to filter the wastewater; although, it is preferable to use at least a two or more layered sand filter for more efficient filtering.
In operation, wastewater flows into the top of the tank. The wastewater is then filtered through the several layers of the aggregate until the wastewater reaches the bottom of the tank. At the bottom of the tank, the filtered wastewater is then discharged to other portions of the septic system. As is known in the art, the different sized aggregates will filter different sized materials from the wastewater.
However, the use of sand filters pose several problems which decrease the efficiency of the filter and thus the cleaning of the wastewater. First, the top or finer layers of aggregate have a tendency to migrate into the more course layers of aggregate. This migration affects the filtering properties of the system, and leads to the need to completely remove and replace all of the aggregate from the tank. This is a time consuming and costly procedure. Second, compaction of the aggregates also occurs within these systems. Compaction results in puddling of the wastewater at the top of the tank due to lack of air spaces within the several layers of the aggregate. Much like migration, the aggregate within the tank must be replaced in order to correct the compaction of the aggregate. Third, channeling also occurs in these types of sand filters; that is, a channel or tunnel will be formed through all of the aggregate layers. This leads to poor filtering of the wastewater and the need, again, to replace all of the aggregate within the tank. The present invention is adapted to solving these and other problems.